Reviewed by Lexie CornerJan 21 2025
A study published in Advanced Science by Dr. Park Jun-woo’s team at KERI's Next Generation Battery Research Center addresses a key challenge to the commercialization of lithium-sulfur batteries through the development of large-area, high-capacity prototypes.
Lithium-sulfur batteries, which use lithium metal as the anode (–) and sulfur as the cathode (+), have a theoretical energy density over eight times that of lithium-ion batteries. These batteries are cost-effective and environmentally friendly, relying on abundant sulfur rather than expensive rare earth materials. Lithium-sulfur batteries are considered critical for advancing lightweight, long-lasting energy storage solutions, particularly in applications such as urban air mobility (UAM).
However, a significant barrier to commercialization has been the formation of lithium polysulfides during charge and discharge cycles. These intermediate compounds migrate between the anode and cathode, causing unwanted chemical reactions that degrade the battery's lifespan and performance.
To address this, Dr. Park’s team developed a novel method incorporating oxygen functional groups with single-walled carbon nanotubes (SWCNTs). The oxygen functional groups improve the dispersion of SWCNTs within the battery, while SWCNTs, with electrical conductivity comparable to copper and strength exceeding steel, stabilize the electrode. This stabilization allows the electrode to accommodate expansion during charge-discharge cycles and effectively controls the diffusion and dissolution of lithium polysulfides, reducing sulfur loss.
The flexibility of SWCNTs and the solvent-friendly (hydrophilic) properties of the oxygen functional groups enable the formation of uniform, smooth electrode surfaces, facilitating the production of large-area, high-capacity batteries.
Using this approach, the research team created a flexible, thick electrode measuring 50×60 mm and assembled it into a 1,000 mAh (1 Ah) pouch-type lithium-sulfur battery prototype. The prototype demonstrated strong performance, retaining over 85 % of its capacity after 100 charge-discharge cycles.
Our technology has not only overcome the biggest challenge of the lithium–sulfur battery through the combination of SWCNT and oxygen functional groups, but also achieved the design and prototype development of large-area, high-capacity flexible electrodes. This is a comprehensive result.
Dr. Park Jun-woo, Study Corresponding Author, Korea Electrotechnology Research Institute
Jun-woo added, “We have laid the foundational framework that can be applied in actual industrial settings, marking a significant achievement that opens up the practical commercialization potential of next-generation lithium–sulfur batteries.”
KERI, which has completed a domestic patent application for this development, anticipates significant interest from industries requiring next-generation lithium-sulfur batteries, including electric vehicles, aircraft, urban air mobility (UAM), and ESS. The institute's focus now is on identifying potential clients and facilitating technology transfer.
KERI is a government-funded research institute under the Ministry of Science and ICT’s National Research Council of Science and Technology (NST). This research was conducted as part of the Global Top Strategic Research Group project (Strategic Research Group for Innovation in Market-Leading Next-Generation Secondary Batteries) and the KERI project on lithium-sulfur batteries.
Journal Reference:
Heo, J., et al. (2025) A Promising Approach to Ultra-Flexible 1 Ah Lithium–Sulfur Batteries Using Oxygen-Functionalized Single-Walled Carbon Nanotubes. Advanced Science. doi.org/10.1002/advs.202406536